[S390] ftrace: disable tracing on idle psw
Disable tracing on idle psw. Otherwise it would give us huge
preempt off times for idle. Which is rather pointless.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 3e2c05c..04f8c67 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -136,9 +136,12 @@
return;
}
trace_hardirqs_on();
+ /* Don't trace preempt off for idle. */
+ stop_critical_timings();
/* Wait for external, I/O or machine check interrupt. */
__load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
PSW_MASK_IO | PSW_MASK_EXT);
+ start_critical_timings();
}
void cpu_idle(void)